Aqueous monoethanolamine (MEA) at concentrations of 5 and 7 M was degraded with 100 mL/min of 98% O2/2% CO2 (98 mL/min O2), with oxygen mass transfer achieved by vortexing in a low-gas-flow degradation apparatus. Degraded samples were analyzed by ion chromatography (IC) and high-pressure liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) for oxidative degradation products. In a high-gas-flow apparatus, 7.5 L/min of 83% N2/15% O2/2% CO2 (1125 mL/min O2) was sparged through a mechanically agitated 5 M MEA solution. A Fourier transform infrared (FTIR) analyzer collected continuous gas-phase data. Formate (HCOO−), hydroxyethyl formamide (HEF), and hydroxyethyl imidazole (HEI) account for 92% of degraded carbon at low-gas-flow conditions and 18−59% of degraded carbon at high-gas-flow conditions. Oxalate (C2O4 2−), oxamide (C2H4N2O2), glycolate (HOCH2COO−), acetate (CH3COO−), carbon monoxide (CO), ethylene (C2H4), formaldehyde (CH2O), and acetaldehyde (CH3CHO) are oxidation products in lower concentrations. Ammonia (NH3), HEF, and HEI account for 84% of degraded nitrogen at low-gas-flow conditions and 83−92% at high-gas-flow conditions. Nitrogen oxides (NO x ), present in lower concentrations, are stripped from solution at high-gas-flow conditions and retained in the degraded solution at low-gas-flow conditions and oxidized to nitrite/nitrate (NO2 −/NO3 −). A comparison of product rates to MEA losses shows that 25−50% of products remain unaccounted for in unknown HPLC peaks. Oxygen consumption rates vary from 1 to 2 mM/h, whereas the overall oxygen stoichiometry is 0.75 mol of O2/mol of MEA degraded.

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In vitro 3D cell models have been accepted to better recapitulate aspects of in vivo organ environment than 2D cell culture. Currently, the production of these complex in vitro 3D cell models with multiple cell types and microenvironments remains challenging and prone to human error. Here, a versatile ink comprising a 4‐arm poly(ethylene glycol) (PEG)‐based polymer with distal maleimide derivatives as the main ink component and a bis‐thiol species as the activator that crosslinks the polymer to form the hydrogel in less than a second is reported. The rapid gelation makes the polymer system compatible with 3D bioprinting. The ink is combined with a novel drop‐on‐demand 3D bioprinting platform, designed specifically for producing 3D cell cultures, consisting of eight independently addressable nozzles and high‐throughput printing logic for creating complex 3D cell culture models. The combination of multiple nozzles and fast printing logic enables the rapid preparation of many complex 3D cell cultures comprising multiple hydrogel environments in one structure in a standard 96‐well plate format. The platform's compatibility for biological applications is validated using pancreatic ductal adenocarcinoma cancer (PDAC) and human dermal fibroblast cells with their phenotypic responses controlled by tuning the hydrogel microenvironment.

A HTP 3D bioprinted cell migration platform that has broad applications across quantitative cell and cancer biology as well as drug screening.